Demonstration of anaerobic stabilization of black water in accumulation systems under tropical conditions

Chaggu, E.J.; Sanders, W.T.M.; Lettinga, G.

doi:10.1016/j.biortech.2006.10.029

Cited by 21 publications

(9 citation statements)

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“…Assuming a waste loading of 100 g COD /p/d and the typical occupancies of 35 and 17 at Central and North, the estimated biogas yield was 0.12 and 0.16 m 3 biogas /kg COD . This biogas yield is lower than the median of 0.20–0.25 found in previous studies (Lettinga et al , 1993; Kujawa-Roeleveld et al , 2003; Chaggu et al , 2007; Mang and Li, 2010; Tilmans et al , 2014) and 0.37 m 3 biogas /kg COD in the laboratory study (Colón et al , 2015). Several explanations exist for the alleged lower biogas yield.…”

Section: Resultscontrasting

confidence: 54%

“…The process is robust and efficient, has low sludge production, can withstand high organic loading rates, and has less operational complexity compared to other traditional wastewater treatment methods (Rittmann and McCarty, 2001). Previous studies found an expected biogas production of 20–25 L per person per day (L/p/d) for domestic sewage (Lettinga et al , 1993; Kujawa-Roeleveld et al , 2003; Chaggu et al , 2007; Mang and Li, 2010; Tilmans et al , 2014) and 28–35 L/p/d for fecal sludge (Kujawa-Roeleveld et al , 2006; Lohri et al , 2010), corresponding to 120–210 Wh/p/d of energy recovered.…”

Section: Introductionmentioning

confidence: 99%

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On-Site Fecal Sludge Treatment with the Anaerobic Digestion Pasteurization Latrine

Forbis-Stokes

O'Meara

Mugo

et al. 2016

Environmental Engineering Science

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The Anaerobic Digestion Pasteurization Latrine (ADPL) is a self-contained and energy neutral on-site sanitation system using anaerobic digestion of fecal sludge to generate biogas and then uses the biogas to pasteurize the digester effluent at 65–75°C to produce a safe effluent that can be reused locally as a fertilizer. Two ADPL systems were installed on residential plots with 17 and 35 residents in a peri-urban area outside of Eldoret, Kenya. Each system comprised three toilets built above a floating dome digester and one heat pasteurization system to sanitize the digested effluent. ADPLs are simple systems, with no moving parts and relying on gravity-induced flows. Adoption at the two sites was successful, and residents reported that the systems had little to no odor or flies. ADPLs were monitored for biogas production and temperatures in the pasteurization system. ADPLs serving 17 and 35 residents produced on average 16 and 11 Lbiogas/person/day (maximum of 20 and 15 Lbiogas/p/d), respectively. The temperature in the sterilization system was greater than 65°C on 58% and 87% of sampling days during the most stable period of operation. Treated effluent was analyzed periodically for chemical oxygen demand (COD), biochemical oxygen demand (BOD), total ammonia nitrogen (TAN), pH, and fecal coliform (FC). On average, the effluent at the two locations contained 4,540 and 6,450 mg COD/L (an 85% or 89% reduction of the estimated input), 2,050 and 3,970 mg BOD/L, and 2,420 and 4,760 mg NH3-N, respectively, and greater than 5 log reductions of FC (nondetectable) in the sterilization tank. Results from this field study show that anaerobic digestion of minimally diluted fecal sludge can provide enough energy to pasteurize digester effluent and that the ADPL may be a suitable option for on-site fecal sludge treatment.

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Section: Resultscontrasting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

On-Site Fecal Sludge Treatment with the Anaerobic Digestion Pasteurization Latrine

Forbis-Stokes

O'Meara

Mugo

et al. 2016

Environmental Engineering Science

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“…The influence of EC on CST is likely due to the correlation to NH4-N (r=0.6, see supplemental material Table S2). High NH4-N concentrations could also inhibit anaerobic digestion which could influence dewatering rate [56,57]. It was hypothesized that crude protein as a metric of EPS would correlate to increased CST, as protein is a major component of EPS, and EPS increased CST in wastewater sludge [58,59].…”

Section: Influence Of Faecal Sludge Characteristics On the Dewateringmentioning

confidence: 99%

Cross-country analysis of faecal sludge dewatering

Gold

Harada

Therrien

et al. 2017

Environmental Technology

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Dewatering of faecal sludge (FS) is indispensable for adequate FS management. However, comprehensive knowledge is lacking on FS dewatering performance. This study compared the dewatering performance of FS from different countries and onsite sanitation technologies, to assess influential characteristics on dewatering, and to compare dewatering performance of FS with wastewater sludge. We collected 73 FS samples from septic tanks, lined pit latrines, unlined pit latrines and johkasou tanks in Uganda, Vietnam and Japan, and 18 samples of wastewater sludge in Switzerland. Capillary suction time (CST) and total solids (TS) of centrifuged sludge (%TS) were determined as metrics of dewatering rate and dewaterability, respectively, together with relevant sludge characteristics. Data were analysed by bootstrapping comparison of median results of each sample category and by bootstrapping multiple regression analysis to quantify the relative importance of sludge characteristics on dewatering performance. Results showed that the dewatering rate was significantly different between FS from different technologies, whereas dewaterability was significantly different within the same technology. FS had a significantly lower dewatering rate than wastewater sludge. In contrast, FS dewaterability was greater than wastewater sludge. However, this could be attributed to higher concentrations of sand in FS. Electrochemical properties such as NH-N and surface charge had the strongest correlation to dewatering rate, and solid properties such as sand content and total volatile solids to dewaterability. The results identify potential characteristics that could explain and predict the high variability of FS dewatering performance that is observed in the field.

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“…Septic tanks, cesspools and related onsite systems have widely been used for sanitation in rural areas, in both developed and developing countries. Anaerobic digestion is more recent and is becoming more common for household fecal waste treatment because of the energy benefits ( Chaggu et al., 2007 ; Forbis-Stokes et al., 2016 ; Kujawa-Roeleveld et al., 2003 ; Lohri et al., 2010 ; Mang and Li, 2010 ; Tilmans et al., 2014 ). These technologies, however, only reduce solid and organic concentrations from the waste stream, resulting in effluents still high in nutrients and pathogens.…”

Section: Introductionmentioning

confidence: 99%

Nutrient removal from human fecal sludge digestate in full-scale biological filters

et al. 2020

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There is a great need for simple methods for digestate management for potential household sanitation systems based on anaerobic digestion of minimally diluted fecal waste in countries that lack safe sanitation. Herein, a full-scale three-stage filter for nitrogen and phosphorus removal from anaerobic digester effluent was implemented in Madagascar. It included a trickling filter with crushed charcoal (for aerobic nitrification), a submerged anaerobic filter with bamboo chips (for denitrification), and a submerged filter with scrap iron (for phosphorus removal). All filter materials were sourced locally. Three parallel replicate systems were operated in two sequential 8-week phases for a total of 16 continuous weeks. Though the influent feed was not as expected, with much of nitrogen in the feed coming in as organic N and not as NH 3 –N, the filters still removed 38–49% of total incoming nitrogen. The filters achieved high rates of nitrogen transformation along with removing solids (73–82% turbidity removal), chemical oxygen demand (67–75% removal), and phosphorus (31–50% removal). Overall, the reaction rates from this full-scale study were in line with previous lab-scale investigations with scaled-down systems, supporting their application in real-world scenarios. Based on this study, simple effluent filters can support nutrient removal for small-scale and onsite fecal sludge treatment systems.

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Demonstration of anaerobic stabilization of black water in accumulation systems under tropical conditions

Cited by 21 publications

References 1 publication

On-Site Fecal Sludge Treatment with the Anaerobic Digestion Pasteurization Latrine

On-Site Fecal Sludge Treatment with the Anaerobic Digestion Pasteurization Latrine

Cross-country analysis of faecal sludge dewatering

Nutrient removal from human fecal sludge digestate in full-scale biological filters

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